I am going to start with a web application with a single servlet that has the @DataSourceDefinition annotation and see whether I can reproduce the bug. If unable to reproduce, then I will have to look at your ear setup.

Update: I have used the mvn archetype for JBoss that lets me create an ear with ejb jar and a web archive. Let me see if I can reproduce.

When the vault functionality was introduced, we started with the security subsystem. But then the AS7 architects opined that it is suitable at the server/domain level. So that is where it went. But I did not remove the security subsystem vault.